Cost reduction in irrigation networks by an efficient use of Pressure Reducing Valves

The cost effective design of hydraulic networks has been traditionally studied from the point of view of the relationship between hydraulic variables and economic parameters, with piping being the main element studied. The reason is clear: the piping is by far the most costly item of a projected network. However it is not usual to find an explicit consideration of the influence that pipe thickness has on the cost of the network because of the added difficulty that this aspect poses to formulating the problem of optimization. In irrigation networks, which are typically branched, it is advisable to place Pressure Reducing Valves (PRV’s) to fulfil three main goals: 1) to control the flow rate extracted by users, 2) to ensure uniform irrigation and 3) to reduce the pipe measure. In relation to this last goal, the authors present a method for reducing network cost through the reduction of the pipe pressure by means of an efficient use of PRV’s Its principal characteristics are: 1) the method is based on the principles of Dynamic Programming and 2) it is independent of the sizing of the diameters of the network.